DATA_SET_DESCRIPTION |
Data Set Overview
=================
THIS DATA SET CONTAINS ELECTRON PARAMETERS IN THE PLS ENERGY
RANGE (10-5950 EV) AT SATURN DURING THE VOYAGER 2 ENCOUNTER.
PARAMETERS ARE CALCULATED IN SEVERAL WAYS. TOTAL MOMENT
DENSITY AND TEMPERATURE ARE GIVEN. EACH ELECTRON SPECTRUM IS
ALSO FIT WITH A THERMAL COMPONENT AND 1-3 HOT COMPONENTS
DEPENDING ON HOW MANY MAXWELLIANS ARE NEEDED TO FIT THE ENTIRE
DISTRIBUTION. THE MOMENT DENSITY AND TEMPERATURE OF THE HOT
COMPONENT IS CALCULATED AFTER THE THERMAL COMPONENT IS
SUBTRACTED FROM THE SPECTRUM. THE CHI-SQUARE VALUE FOR EACH
FIT IS GIVEN. THE SPACECRAFT CHARGE IS NOT CALCULATED
CONSISTENTLY, AND MAY RESULT IN FACTOR OF 2-3 ERRORS IN THE
THERMAL ELECTRON DENSITY. DATA IS UNRELIABLE INSIDE 6 RS AND
IN THE OCCULTATION REGIONS. A COMPLETE DESCRIPTION OF THIS
DATA SET IS IN SITTLER ET AL. (1983). DATA FORMAT: THE DATA
SET IS IN ASC FORMAT AND CAN BE READ USING THE FOLLOWING
FORTRAN STATEMENT:\n
READ(22,999) JTIME,IMAX,IFLY,EDATA
FORMAT(8I6,17G12.5,/,1X,10G12.5)
THE PARAMETER DEFINITIONS ARE:
NAME TYPE DEFINITION JTIME(1-6) I*4 YR,DAY,HR,MIN,SEC,MSEC IMAX
' # OF POINTS IN SPECTRUM (INCLUDES 11 PTS BELOW 10 EV FOR MOM
INTEGRALS) IFLY ' FLAG = 0 FOR CRUISE AND =1 FOR ENCOUNTER
EDATA(1) R*4 THBN(ANGLE BETWEEN DCUP NORMAL AND B VECTOR) 2 '
RNE MOMENT ELECTRON DENSITY (/CM**3) 3 ' RTE ' ' TEMPERATURE
(EV) 4 ' PHISC SPACECRAFT POTENTIAL (VOLTS) 5 ' RNC COLD
ELECTRON DENSITY (/CM**3) 6 ' SGNC STANDARD DEVIATION OF RNC
(/CM**3) 7 ' RTC COLD ELECTRON TEMPERATURE (EV) 8 ' SGTC
STANDARD DEVIATION OF RTC (EV) 9 ' CHIC CHI-SQUARE OF COLD FIT
10 ' RNH1 1ST HOT ELECTRON DENSITY (/CM**3) 11 ' SGNH1 STANDARD
DEVIATION OF RNH1 (/CM**3) 12 ' TH1 1ST HOT ELECTRON
TEMPERATURE (EV) 13 ' SGTH1 STANDARD DEVIATION OF TH1 (EV) 14 '
CHIH1 CHI-SQUARE OF 1ST HOT FIT 15 ' RNH2 2ND HOT ELECTRON
DENSITY (/CM**3) 16 ' SGNH2 STANDARD DEVIATION OF RNH2 (/CM**3)
17 ' TH2 2ND HOT ELECTRON TEMPERATURE (EV) 18 ' SGTH2 STANDARD
DEVIATION OF TH2 (EV) 19 ' CHIH2 CHI-SQUARE OF 2ND HOT FIT 20 '
RNH3 3RD HOT ELECTRON DENSITY (/CM**3) 21 ' SGNH3 STANDARD
DEVIATION OF RNH3 (/CM**3) 22 ' TH3 3RD HOT ELECTRON
TEMPERATURE (EV) 23 ' SGTH3 STANDARD DEVIATION OF TH3 (EV) 24 '
CHIH3 CHI-SQUARE OF 3RD HOT FIT 25 ' CHI CHI-SQUARE FOR TOTAL
FIT 26 ' RNH MOMENT HOT ELECTRON DENSITY (/CM**3) 27 ' RTH
MOMENT HOT ELECTRON TEMPERATURE (EV) IN COMPUTING RNH1,TH1 WE
USED THE 3RD TO 7TH CHANNELS ABOVE THE BREAKPOINT ENERGY EB1
AND SUBTRACTED THE COLD COMPONENT FC FROM FE (OBSERVED) BEFORE
DOING THE FIT. IN REALITY THIS FIT WAS DONE ITERATIVELY
BETWEEN THE COLD AND HOT COMPONENT FITS (FC=FE-FH AND FH=FE-FC
ETC.). A SIMILAR APPROACH WAS USED IN COMPUTING RNH3,TH3 FOR
WHICH A MAXWELLIAN FIT WAS DONE TO THOSE CHANNELS ABOVE EB2.
THE PARAMETERS RNH2,TH2 WERE FIT TO THE UPPER 5 (3 MIN)
CHANNELS (GENERALLY ABOVE EB2). THIS FIT WAS PRIMARILY DONE TO
ALLOW PROPER ESTIMATION OF FE TO THE HIGH ENERGY PORTION OF THE
SPECTRUM. IN MANY CASES THERE ARE NOT SUFFICIENT POINTS TO
COMPUTE RNH3,TH3 AND RNH2,TH2 DO PROVIDE A FAIR REPRESENTATION
OF THE SPECTRUM. IF RNH1=RNH2=RNH3 THEN YOU SHOULD NOT USE THE
2ND AND 3RD FIT PARAMETERS. VALUES OF 1.E32 INDICATE THAT THE
PARAMETER COULD NOT BE OBTAINED FROM THE DATA USING THE
STANDARD ANALYSIS TECHNIQUE. ADDITIONAL INFORMATION ABOUT THIS
DATASET AND THE INSTRUMENT WHICH PRODUCED IT CAN BE FOUND
ELSEWHERE IN THIS CATALOG. AN OVERVIEW OF THE DATA IN THIS
DATA SET CAN BE FOUND IN SITTLER ET AL. (1983) AND A COMPLETE
INSTRUMENT DESCRIPTION CAN BE FOUND IN BRIDGE (1977).
Processing Level Id : 5
Software Flag : Y
Parameters
==========
Sampling Parameter Name : TIME
Data Set Parameter Name : ELECTRON DENSITY
Sampling Parameter Resolution : 96.000000
Sampling Parameter Interval : 96.000000
Minimum Available Sampling Int : 96.000000
Data Set Parameter Unit : CM-3
Sampling Parameter Unit : SECOND
Description
-----------
A derived parameter giving an indication of the mean A
derived parameter equaling the number of electrons per unit
volume over a specified range of electron energy.
energy/electron, assuming the shape of the electron energy
Different forms of electron density are derived spectrum to
be Maxwellian (i.e.highest entropy shape). Given
distinguished by method of derivation (Maxwellian fit, that
the electron energy spectrum is not exactly Maxwellian,
method of moments) or by the some selection criteria (ie.,
the electron temperature can be defined integrally (whereby
the mean energy obtained by integrating under the actual hot
electron and cold electron density). In general, if more
electron energy spectrum is set equal to the integral under
than one electron component is analyzed, either by moment or
fit, a total density will be provided which is the sum of a
Maxwellian, where the temperature is a free parameter for the
electron densities. If the electron do not have a which to
solve), or differentially (whereby the slopes of Maxwellian
distribution the actual distribution can be the actually
electron energy spectrum at various energies are matched to
the slopes of a corresponding Maxwellian). represented as
the sum of several Maxwellians, in which case the density of
each Maxwellian is given. The temperature parameter is often
qualified with a range of applicable energies. temperatures
can be angularly anisotropic. If the electrons do not have a
Maxwellian distribution the actual distribution can be
represented as the sum of several Maxwellians, each with a
separate temperature.
Source Instrument Parameters
============================
Instrument Host ID : VG2
Data Set Parameter Name : ELECTRON DENSITY
Instrument Parameter Name : ELECTRON RATE
Important Instrument Parameters : 1
Instrument Host ID : VG2
Data Set Parameter Name : ELECTRON DENSITY
Instrument Parameter Name : ELECTRON CURRENT
Important Instrument Parameters : 1
Instrument Host ID : VG2
Data Set Parameter Name : ELECTRON TEMPERATURE
Instrument Parameter Name : ELECTRON RATE
Important Instrument Parameters : 1
Instrument Host ID : VG2
Data Set Parameter Name : ELECTRON TEMPERATURE
Instrument Parameter Name : ELECTRON CURRENT
Important Instrument Parameters : 1
Processing
==========
Processing History
------------------
Source Data Set ID : VG2-PLS
Software : UNK
Product Data Set ID : VG2-S-PLS-5-ELE-PAR-96.0SEC
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